Embodiments of the present invention generally relate to a print head for an ink jet printer, and particularly to an ink jet printer having a system for removing ink deposits and residue from a ground plate and catcher.
Conventional continuous ink jet printers supply electrically conductive ink under pressure to a drop generator, which has an orifice or orifices (nozzles) that are typically arranged in a linear array. The ink discharges from each orifice in the form of a filament, which subsequently breaks up into a droplet stream. Individual droplets in the stream are selectively charged in the region of the break off from the filament, and these charged drops are then deflected as desired by an electrostatic field. The deflected drops may proceed to a substrate, whereas undeflected drops are caught in a gutter or catcher and recirculated.
After the printer is shut down for a period of time, ink within the print head dries up, often partially blocking, and sometimes completely clogging, the outer openings to the orifices catcher, and other components therein. Furthermore, during a long shut down period, such as an entire day or weekend, the dried ink accumulates within the orifice or passages attached to the orifice, depending on the type of ink.
Known designs, such as those disclosed by U.S. Pat. Nos. 6,575,556, 5,877,788 and 4,528,996, are used to cleanse the orifices of the print heads. Additionally, a continuous ink jet printer having a print head that closes off the orifice to stop seepage of ink therethrough during periods when printing does not occur is disclosed in U.S. Pat. No. 5,598,197.
Typically, print head cleaning systems and methods are limited to the nozzle, or drop generator. However, ink deposits and residue also accumulate around the catcher and ground plate. Ink droplets often settle on and within the catcher. As ink deposits and residue accumulate on these components, printing quality suffers due to the clogging of the components and conduits therebetween, or due to interference between built-up residue and ink droplets. That is, the recycling rate of ink and other fluids through these components decreases as the accumulation of deposits and residue increases. Often, the ink jet printer is completely shut down in order for an operator to manually clean these components, thereby precluding use of the printer.
Thus, a need exists for a system and method of cleaning various components of a print head of an ink jet printer. Overall, a need exists for an efficient system and method of cleaning a print head of an ink jet printer.